Controlling vegetation with hydrocarbon mono-nitrogen heterocyclic aminocarbodithioates



Shite htates lies 1 3,078,153 CONTROLLING VEGETATION WITH HYDRO- CARBGN MONO-NITROGEN HETERQCY- CLIC AMENDCARBODHTHIOATES Marion W. Harman, Nitro, and John I. DAmico, Charleston, W. Va, assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Get. 8, 1959, Ser. No. 845,079 9 Claims. (Cl. 71-25) This invention relates to methods of destroying or controlling vegetation and to herbicidalcompositions. More particularly it relates to methods of destroying or controlling vegetation which comprises applying thereto a toxic concentration of a phytotoxic ester of a dithiocarbamic acid.

General objects of the invention are to provide useful compositions which are toxic to living plants and to provide methods for their use to accomplish various desirable results. A further object is to provide compositions and methods for the destruction of noxious vegetation. Another object is to destroyv weeds by applying a toxic concentration of the composition to foliage after emergence. A particular object of the invention is to provide outstanding grass-specific pre-ernergence herbicides and methods for using them. A further particular object is to control weeds growing in cotton, radish and corn fields without injuring the crop. Other and further objects will v be apparent from the detailed description which follows.

A method of destroying or controlling undesired vegecation, according to this invention, comprises applying thereto a toxic concentration of a phytotoxic ester of a dithiocarbamic acid possessing the general formula S R-i l-SX R in the above formula represents a hydrocarbon mononitrogen heterocyclic radical. Examples of R are the radicals derived by removal of the hydrogen from the nitrogen of ethylenirnine, tetrahydropyridine, pyrrolidine, 2-n1ethylpyrrolidine, 2,3-dimethylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine, Z-methylpiperidine, 4-rnethyl piperidine, S-ethyl-Z-methylpiperidine, S-ethyl-S-rnethylpiperidine, 2,3-dimethylpiperidine, 2,4-dimethylpiperidine, 2,4,6-trimethylpiperidine and hexamethylenimine. X may be lower alkyl, lower monoolefinic hydrocarbon or halogen substituted lower monoolefinic hydrocarbon. EX- amples are methyl, ethyl, butyl, propyl, isopropyl, ailyl, 2-chl0rallyl, Z-bromoallyl, 2fluoroallyl, 2-iodoaliyl, 3-chloroallyl, 3-bromoallyl, 3-tiuoroallyl, 3-iodoallyl, 3-chloro-2-butenyl, 3bromo-2-butenyl, S-luorQ-Z-butenyl, 3-iodo-2-butenyl, 2,3-dichloroallyl, 3,3-dichloroallyl, 2,3- dichloro-2-butenyl, 2,3-diiodo-2-butenyl, Z-liuoro-B-chloroallyl, 2,3-dibromoallyl, 3,4,5-trifiuoro-3-butenyl and 2,3,3-trichloroallyl.

The phytotoxic esters of. this invention comprise weed killers having both pro-emergent and post-emergent activity. Accordingly, by applying the toxicant to the plant is meant any means whereby the toxicant is brought into contact With living plants which latter include germinating seedlings, as for example by application to the ground before the plants emerge or by direct application to the foliage. In general, the compounds are outstanding grassspecific pre-emergent herbicides. They also control one of the most prevalent broadleaf Weed families, pigweed. The grasses controlled include the three major Midwest weedy grasses, crab grass, foxtail and barnyard grass. Tillering and other formative effects are often observed and by careful control of the concentration, the compositions can be used for sterilization of the soil where desirable.

The toxicants may be applied conveniently in the form of a spray containing the active ingredient in a concentration within the range of 0.1l0.0% by weight. Thorough coverage of the foliage is effective for contact killing. For pro-emergence control of plants amounts within the range of A to pounds per acre may be used and within the range of 30-100 pounds the compounds efiect soil sterilization.

Although most of the esters are insoluble in water, they are soluble in common organic solvents. They may be dispersed directly in water or a solution in an organic solvent emulsified in aqueous medium by the aid of a dispersing agent. As dispersing and wetting agents there may be employed soft or hard sodium or potassium soaps, alkylated aromatic sodium sulfonates such as sodium dodecylbenzenesulfonate, an amine salt, as for example dibutylammonium dodecylbenzenesulfonate, alkali metal salts of sulfated fatty alcohols, ethylene oxide condensation products of any of the following: alkyl phenols, tall oil and higher mercaptans. These are illustrative only of a large class of materials available and it will be appreciated that other dispersing and wetting agents may be used. Formulation of dry compositions is accomplished by mixing with finely dividedor ganular solid carriers. Suitable carriers comprise talc, clay, pyrophyllite, silica and fullers earth. Usually the toxicant will be only a minor proportion. The dry formulation may be applied directly or dispersed in aqueous medium before application. It the latter, it is advantageous to incorporate a wetting or dispersing aid into the formulation.

Table I illustrates the pro-emergent herbicidal activity of typical examples. The ester was emulsified in water and the emulsion applied as a spray. In this manner, the active ingredient was applied to the ground of seeded plots before any plants emerged. The plants studied included most of the following in each test: morning glory, wild oat, brome grass, rye grass, mustard (radish), beetsugar, corn, foxtail, barnyard grass, crab grass, pigweed, cotton and wild buckwheat. Fourteen days after application of the toxicants results were observed and recorded. The number of seeds emerging was converted to weighted herbicidal ratings based on average percent germination of any particular seedlot times an injury factor. This evened irregularities of herbicide ratings of seeds which varied in percent germination. The injury factor takes into consideration any plants not expected to survive. Thus, phytotoxicity ratings were based on the number of plants which emerged and-would survive as observed two Weeks after planting. Herbicidal ratings were assigned by means of the following conversion scale:

Percent emergence: Phytotoxicity ratings 0-25% 3 or severe. 26-50% 2=0r moderate. 51-75% lor slight. 76-l00% 0 or none. Table I Active ingredient Lbs. [acre Results observed Allyl l-pyrrolidine- 25 Severe phytotoxlcity to wild oats,

carbodithioate. brome grass, rye grass, beetsugar, foxtail, barnyard grass, crab gra's and pigweed. 3,3-dichloroallyll-pyrro- 25 Severe phytotoxicity to morning lidine-carbodithicate. glory, rye grass, foxtail, barnyard1 grass, crab grass and pigwee Ois-and trans-2,3-diehlo- 25 Severe phytotoxloity to brorne roallyl l-pyrrolidinegrass, foxtail, barnyard grass, carbodithioate. crab grass and pigweed; moderate phytotoxicity to morning glory and rye grass.

Allyl l-piperidine-car- 25 Severe phytotoxicity to wild oats,

bodithioate. brome grass, rye grass, beetsugar, foxtail, barnyard grass, crab grass and pigweed; moderate I phytotoxieity to morning glory. 2-chloroallyl1-piperi- 25 Severe phytotoxicity to brome dine-earbodithioategrass, rye grass, toxtail, barnyard grass, crab grass and piglutrleed moderate phytotoxiclt y to as s.

Table I-Continued Active ingredient Lbs/acre Results observed Oisand trans-2.3dichlo 25 Severe phytotoxicity to brome roallyll-p lper1d1negrass, rye grass, barnyard grass; carbodithioate. moderate phytotoxicity to morning glory, toxtail, crab grass and pigweed.

3,3-dichloroallyl l piper- 10 Severe phytotoxiclty to rye grass, idine-carbodithroate. barnyard grass and crab grass.

Allyl 5eth yl-2-methyl- 25 Severe phytotoxicity to morning l-piperidinecarbodiglory, wild oats, brome grass, thioate. rye grass, beet-sugar, foxtail.

barnyard grass, crab grass and pigweed.

2-chloroal1y1 Methyl-2- 3 Severe phytotoxicity to wild oats, thy -p p brome grass, rye grass, toxtail, carbodithioate. barnyard grass, crab grass and pigweed; moderate ph ytotoxicity to beet'sugar.

S-chloro-Z-butenyl 5- 25 Severe phytotoxlcity to wild oats, ethyi-2-methyl-i-pibrome grass, rye grass, foxtail, psridine carbodithwbarnyard grass and crab grass. as e.

2,3-dichloroellyl S-ethyl- 25 Severe phytotoxlcity to wild oats z-methyl-l-piperidlnebrome grass, rye grass, ioxtail, carbodithioate. barnyard grass, crab grass, pigweed and buckwheat. 3-chloroallyl 5cthy l-2- 25 Severe phytotoxicity to wild oats, methyl-l-piperidmebrome grass, rye grass, foxtail, carbodithioate. barnyard grass, crab grass and pigweed, moderate phytotoxicity to beet-sugar and buckwheat.

Methyl 5-ethyl-2-meth- 25 Severe phytotoxicity to morning yl-1-p1perid1necarboglory, wild oats, brome grass, dithioete. rye grass, foxtail, barnyard grass,

crab grass and pigweed; moderate phytotoxicity to buckwheat and beet-sugar.

Ethyl 5-ethyl-2-methyl- 5 Severe phytotoxicity to wild oats, l-piperidinecarbodibrome grass, rye grass, foxtail, thioate. barnyard grass and crab grass;

moderate phytotoxicity to morning glory and pigweed. a1l31 hy1- 25 Severe phytotoxicity to wild oats, 2-methyl-l-pipcndlnebrome grass, rye grass, foxtail, carbodithioate. barnyard grass, crab grass and pigweed.

2-chloroallyi 2-methyl-1- 25 Severe phytotoxiclty to wild oats, piperidinecarbodibrome grass, rye grass, foxtail. thioate. barnyard grass, crab grass and pigwced; moderate phytotoxicity to morning glory and beet-sugar. 2-chloroallyl 2,4,5-tr1- 25 Severe phytotoxicity to morning methyl-l-piperidmeglory, wild oats, brome grass, carbodithioate. rye grass, mustard (radish), beetsugar, barnyard grass, crab grass and pigweed; moderate phytotogcity to buckwheat and fox- Allyl 2,4,6-trimethyl 5 Severe phytotoxiclty to wild oats, i-piperidinecarbobrome grass, rye grass, barnyard dithioate grass, crab grass and pigweed.

2-chloroal1yl 2,4-di- 5 Severe phytotoxicity to wild oats, methyl-l-piperrdinerye rass, crab grass and pigweed; carbodlthlon c m0 crate phytotoxicity to morningglory, brorne grass and barnyar gross.

2- l r fll1Y1 -Q 5 Severe phytotoxicity to wild oats, methyl-l-piperidlnebrome grass, rye grass, barnyard carbodithioate grass, crab grass and pigweed;

moderate phytotoxicity to beetsugar.

Cis-and trans-2,3-di- 25 Severe phytotoxicity to wild oats, chloroallyl 2,4,t 5-t rlrye grass, beet-sugar, barnyard methyl-i-piperidinegrass and crab grass. carbodithioato 2-chloroallyl 5 Severe phytotoxicity to wild oats, 1-pyrr0 1id mecheat grass, rye grass, beet-sugar carbodithioate and ioxtail.

3-ohloroallyl Severe phytotoxicity to wild oats,

l-pyrrolidinecheat grass and beet-sugar; modcarbodithioate erate phytotoxicity to rye grass and mustard (radish). 2-chloroally12,6'dl- 25 Severe phytotoxicity to plgweed, methyl-l-pipendinecrab grass, barnyard grass, rye carbodithioate grass and Wild oats.

Allyll 2,3,6-tetrahydro- 25 Severe phytotoxicity to pigweed; pyridinecarbomoderate phytotoxicity to Wild. dithioate oats, rye grass and crab gross.

2,3,3-trichloroallyl 25 Severe phytotoxicity to morning l-hcxamethylenimmeglory, crab grass, pigweed and carbodithioate sorghum; moderate phytotoxicity to wild oats, rye grass and foxtail.

2-chloroo1lyl1-hexa- 25 Severe phytotoxieity to morning xncthylenimiuecarboglory, wild oats, rye grass, radish dithionte (mustard), sugar beet, loxtail,

crab rass, pigweed, soybean, Wild uckwheat, tomato and sorghum. 2,3dichloroallyl1-hexa- 25 Severe phytotoxlcity to wild oats,

methyleniminecarborye grass. ioxtail, crab grass, pigdithioate weed and sorghum.

Ally] l-hexamethylen- 25 Severe phytotoxicity to morning iminecarbodrthioate glory, wild oats, brome grass, rye grass, sugar beet, ioxtail, crab grass, pigweed, soybean and sorghum.

From these data it is quite apparent that the toxicants shows a marked specific action on weedy grasses and pig- Wccd. In no case were corn or cotton seeds affected by the treatment.

Hcrbicidal activity on foliage contact is illustrated by the data recorded in Table II. A spray containing the concentration of the active ingredient shown in the table was applied to the foliage of grasses, to the foliage of bean plants and to the foliage of a mixture of broadleaved plants. The mixture is indicated in the table as Broadleaf.

Table II Phytotoxic ty rating Percent Active ingredient cone.

Grass Bean Broadleaf Allyl 1-pyrrolidiuecarbodithioate-. 0. 5 2+ 2 3+ 3,3dichloroallyl l-pyrrolidinecarbodithioate 0.5 2+ 1 2 3 Cisand trans-2,3-dichloroallyl Lpyrrolid inecarbodithioate 0. 5 3+ 1 2 Allyl l-pipcrldinecarbodithioote g 1 3 2-chloroallyl l-piperidinecarbo dithioate 0. 5 3 2+ Oisand trans-2,3-dichloroallyl l-piperidinecarbodithioate O. 5 2 2+ 2 3,3-dichloroa1lyl l-piperidlnecarbodithloate 0. 5 1+ 1 2 2,3-dichloroallyl 5-ethyl-2-methyll-piperidineearbodithioate 0. 5 1 2 1 3-chloroallyl 5-ethyl-2-mcthy1- 0. 5 2 3 2 l-piperidinecarbodithioate. 0. 2 2 1 l Ethyl 5-ethyl-2-metl1yl-1-pipcridinecarbodithioate 0. 5 2 1 2 2-ehloroallyl Z-methyl-l-piperidine 0.5 2 4 0 3+ carbodithioate. 0.2 2 1 2+ 2-chloroallyl 2,4,(Ltrimethyll-piperidinecarbodithioate 0. 5 2 2 1 2-chloroally] QA-dimethyb i-piperidinecarbodithioate- 0. 5 3 1 2 3-cl1loro-2-butenyl l-piperidin carbodithioatm 0. 5 2+ 3 1+ 2 z-chloroallyl l-pyrrolldlnecarbo- 8* 3 g a g dithioate. 1 2 1 2 3-cl1loroally1 l pyrrolidinecarbodithionte 0. 5 2 2 1+ 8-chloro-2-butenyl 1-pyrrolidinc earbodithioate 0. 0 2+ 2 2+ 1 50% defoliation. 2 Plants dead. 3 30% defoliation.

The compounds of this invention may be prepared by condensing a salt of a dithiocarbamic acid with a halide containing the desired ester forming radical. The following illustrates in detail typical methods of preparation:

To a stirred solution comprising 35.6 grams (0.5 mole) of pyrrolidine, 80.0 grams (0.5 mole) of 25% sodium hydroxide and 400 ml. of water was added dropwise at 20-25 C. over a period of 15 minutes 38.0 grams (0.5 mole) of carbon bisulfide. After stirring for one hour, 72.7 grams (0.5 mole) of 1,1,3-trichloro-l-propene was added in one portion. The stirred reaction mixture was heated at 5060 C. for 3 hours, then cooled to 25 C. and extracted with 400 ml. of ethyl ether. The other solution was washed with water until neutral to litmus and dried over sodium sulfate. The ether was removed in vacuo at a maximum temperature of -90 C./12 mm. The 3,3-dichloroallyl 1-pyrrolidinecarbodithioate was an amber liquid obtained in 61.6% yield. Analysis gave 5.8% nitrogen and 24.3% sulfur as compared to 5.5% nitrogen and 25.0% sulfur calculated for C H CI NS '19 grams (0.25 mole) of carbon bisulfidc was added dropwise at 20-25 C. over a 15 minute period with stirring to a solution comprising 17.8 grams (0.25 mole) of pyrrolidine, 40 grams (0.25 mole) of 25% sodium hydroxide and 200 ml. of water. Next was added 36.3 grams (0.25 mole) of cisand trans-1,2,3-trichloro-l-propcne and the reaction mixture stirred at room temperature for 24 hours. After cooling to 5 C. the precipitate was filtered, washed with cold water until neutral to litmus and air dried at room temperature. The cisand trans- 2,3-dichloroallyl 1-pyrrolidiuccarbodithioatc was obtained in 73.5% yield as a cream colored, solid melting at 40 41 vC. Analysis gave 5.3% nitrogen and 27.8% chlorine as compared to 5.5% n

gen mononuclear heterocyclic radical containing from 5 itrogen and 27.7% chlorine calto 7 members inclusive and X represents a lower monoolefinic hydrocarbon radical.

culated for CaHnClzNSz.

The physical properties-of other typical examples pre- 2. The method of controlling vegetation which compared in similar manner are summarized in Table Ill. 5 prises applying thereto a toxic concentration of a phyto- Table III id of the general formula esents a saturated hydrocarbon mono-nitro- It is intended to cover all changes and modifications gen rnononuclear heterocyclic radical containing from 5 tion Serial No.

inclusive and X represents a halogen subical. ethcd of controlling vegetation which corntuted lower monoolefinic 3. The rn prises applying thereto a s r e m m 7 .1 mm 0 2 d 00 m 9 1 13 1d n m MI W t a P hydrocarbon rad ion which com- 0 concentrationof a phytohiocarbarnic acid of the general for- 70 l. The method 0 toxic concentration of allyl 1- pyrrolidinecarbcdithioate.

f controlling vegetat prises applying thereto a toxi toxic ester of a dit mula 4. The method of controlling vegetation which comi RC-SX where R represents a saturated hydrocarbon mono-nitro- 75 7 -8 6. The method of controlling vegetation which com- 9. The method of controlling vegetation which comprises applying thereto a toxic concentration of 2-chloroprises applying to soil medium lower alkenyl hexamethyl' allyl S-ethyl-Z-methyl-l-piperidineearbodithioate. eniminecarbodithioate.

7. The method of controlling vegetation which comprises applying thereto a toxic concentration of 2-chloro- 5 References Cited in the file Of this Patent allyl Z-methyl-l-piperidinecarbodithioate. UNITED STATES PATENTS 8. The method of controlling vegetation which comprises applying to soil medium halogen substituted allyl hexamethyleniminecarbodithioate.

2,919,182 Harman et al Dec. 29, 1959 2,941,879 Goodhue June 21, 1960 

1. THE METHOD OF CONTROLLING VEGETATION WHICH COMPRISES APPLYING THERETO A TOXIC CONCENTRATION OF A PHYTOTOXIC ESTER OF A DITHIOCARBAMIC ACID OF THE GENERAL FORMULA 